This project helps investigators to cope with complex equations that model biological systems, including the following efforts: 1) HIV in vitro kinetics (with J. Spouge, D. Dimitrov). A model has been developed and tested to explain oscillating population sizes in simple infection experiments. A paper about this model is in press. 2) Hemoglobins (with K.D. Vandegriff, R.M. Winslow, M. Chavez). Oxygenation and oxidation of hemoglobins are studied by spectrophotometry and singular value decomposition (SVD). We have had several meetings about necessary equipment and procedures for an experiment that will minimize the unwanted occurrence of dimers and oxidation in the hemoglobin-oxygenation equilibrium curve. 3) Kinetics of bacteriorhodopsin (with R.W. Hendler, S. Bose). A review o models of light-intensity- dependent kinetics has been published. 4) Kinetics of cytochrome aa3 (with R.W. Hendler, S. Bose, S. Chan). A paper describing two possible mechanisms for passing electrons to oxygen ha been revised and submitted. 5) Protein-ligand binding (with P.J. Munson, G.E. Rovati). A paper describing a program for nonlinear least squares fitting of kinetic binding data is in press. 6) Magnetic resonance imaging of diffusion (with P. Basser). Gradient sequences are being designed that will optimize the resolution of anisotropic diffusion with as few images as possible to reduce patient discomfort. 7) Thermal transitions in proteins (with J. Ferretti). Conformational changes in protein structure are being studied by circular dichroism and SVD. It now appears that this project will need a major upgrade in equipments to reduce base-line instability. 8) Experimental design for resolving exponential processes in NMR (with G. Weiss and R. Spencer). See section on G. Weiss.